Pop-up valves for selectively opening and closing access to a generally cylindrical waste drain pipe, for example in a bathroom lavatory or sink, are well-known in the art. An example of one such pop-up valve is shown in U.S. Pat. No. 4,380,834.
Typically, the structures making up prior art pop-up valves are placed upon or adjacent a cylindrical waste drain pipe. In one type of prior art pop-up valve, as may best be seen in FIG. 6, the cylindrical waste drain pipe is externally threaded. An internally threaded nut is rotatably secured to the external threads of the cylindrical waste drain pipe.
As the nut is turned in a clockwise or counterclockwise direction, it moves vertically upwardly and downwardly relative to the drain pipe. A rubber seal is positioned at the top of this nut. Accordingly, as the nut is moved upwardly, it urges the adjacent rubber seal element upwardly.
This vertical movement is necessary so that a given pop-up valve can be installed under, and can accommodate, sinks of different styles, sizes, and configurations.
The engagement of this black rubber seal element with the bottom of the sink prevents leakage of water through the floor or base of the sink.
In contrast, as the nut is moved downwardly, it permits the lowering of the rubber seal element away from the underside of the sink, as for example to facilitate replacement of a worn rubber seal.
Certain deficiencies arise from the structure of the above-described prior art pop-up valves. For example, as new rubber seals are moved upwardly towards the bottom of the sink, the inner surfaces of those seals slide and rub against the threads of the drain pipe. Friction results from the sliding of the rubber seal against these threads. This friction makes it more difficult to move the rubber seal upwardly and into position against the bottom of the sink.
However, a more serious problem results from the upward vertical movement of the rubber seal. Particularly, the portion of the rubber seal that abuts against the threads along the exterior of the drain pipe can be damaged as a result of the upward movement relative to, and upon, those threads. Such damage can compromise the ability of the rubber seal to create a water-tight condition at the bottom of the sink.
Other generally relevant prior art includes U.S. Pat. Nos. Des. 244,533; 5,749,105; 5,832,544; 5,946,746; 6,219,861; 6,484,330; 6,725,472; 6,763,533; 3,397,902; 538,301; 4,694,513; 3,795,924; 3,430,990; 3,104,400; 2,672,205; 2,464,332; 2,063,632; 1,811,827; 5,882,043; 4,182,519; 3,150,889; 2,855,003; 2,349,202; 1,059,748; and 1,020,929.
The present invention is provided to solve the problems discussed above and other problems, and to provide advantages and aspects not provided by prior pop-up valves and valve bodies of this type. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings.